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import os
import pathlib
import posixpath
from django.conf import settings
from django.core.exceptions import ImproperlyConfigured
from django.core.exceptions import SuspiciousFileOperation
from django.core.files.utils import FileProxyMixin
from django.core.files.utils import validate_file_name
from django.utils.encoding import force_bytes
def to_bytes(content):
"""Wrap Django's force_bytes to pass through bytearrays."""
if isinstance(content, bytearray):
return content
return force_bytes(content)
def setting(name, default=None):
"""
Helper function to get a Django setting by name. If setting doesn't exists
it will return a default.
:param name: Name of setting
:type name: str
:param default: Value if setting is unfound
:returns: Setting's value
"""
return getattr(settings, name, default)
def clean_name(name):
"""
Normalize the name.
Includes cleaning up Windows style paths, ensuring an ending trailing slash,
and coercing from pathlib.PurePath.
"""
if isinstance(name, pathlib.PurePath):
name = str(name)
# Normalize Windows style paths
clean_name = posixpath.normpath(name).replace("\\", "/")
# os.path.normpath() can strip trailing slashes so we implement
# a workaround here.
if name.endswith("/") and not clean_name.endswith("/"):
# Add a trailing slash as it was stripped.
clean_name += "/"
# Given an empty string, os.path.normpath() will return ., which we don't want
if clean_name == ".":
clean_name = ""
return clean_name
def safe_join(base, *paths):
"""
A version of django.utils._os.safe_join for S3 paths.
Joins one or more path components to the base path component
intelligently. Returns a normalized version of the final path.
The final path must be located inside of the base path component
(otherwise a ValueError is raised).
Paths outside the base path indicate a possible security
sensitive operation.
"""
base_path = base
base_path = base_path.rstrip("/")
paths = list(paths)
final_path = base_path + "/"
for path in paths:
_final_path = posixpath.normpath(posixpath.join(final_path, path))
# posixpath.normpath() strips the trailing /. Add it back.
if path.endswith("/") or _final_path + "/" == final_path:
_final_path += "/"
final_path = _final_path
if final_path == base_path:
final_path += "/"
# Ensure final_path starts with base_path and that the next character after
# the base path is /.
base_path_len = len(base_path)
if not final_path.startswith(base_path) or final_path[base_path_len] != "/":
raise ValueError(
"the joined path is located outside of the base path component"
)
return final_path.lstrip("/")
def check_location(storage):
if storage.location.startswith("/"):
correct = storage.location.lstrip("/")
raise ImproperlyConfigured(
(
"{}.location cannot begin with a leading slash. Found '{}'. Use '{}' "
"instead."
).format(
storage.__class__.__name__,
storage.location,
correct,
)
)
def lookup_env(names):
"""
Look up for names in environment. Returns the first element
found.
"""
for name in names:
value = os.environ.get(name)
if value:
return value
def get_available_overwrite_name(name, max_length):
# This is adapted from Django, and will be removed once
# Django 5.1 is the lowest supported version
dir_name, file_name = os.path.split(name)
if ".." in pathlib.PurePath(dir_name).parts:
raise SuspiciousFileOperation(
"Detected path traversal attempt in '%s'" % dir_name
)
validate_file_name(file_name, allow_relative_path=True)
if max_length is None or len(name) <= max_length:
return name
file_root, file_ext = os.path.splitext(file_name)
truncation = len(name) - max_length
file_root = file_root[:-truncation]
if not file_root:
raise SuspiciousFileOperation(
'Storage tried to truncate away entire filename "%s". '
"Please make sure that the corresponding file field "
'allows sufficient "max_length".' % name
)
name = os.path.join(dir_name, "{}{}".format(file_root, file_ext))
validate_file_name(name, allow_relative_path=True)
return name
def is_seekable(file_object):
return not hasattr(file_object, "seekable") or file_object.seekable()
class ReadBytesWrapper(FileProxyMixin):
"""
A wrapper for a file-like object, that makes read() always returns bytes.
"""
def __init__(self, file, encoding=None):
"""
:param file: The file-like object to wrap.
:param encoding: Specify the encoding to use when file.read() returns strings.
If not provided will default to file.encoding, of if that's not available,
to utf-8.
"""
self.file = file
self._encoding = encoding or getattr(file, "encoding", None) or "utf-8"
def read(self, *args, **kwargs):
content = self.file.read(*args, **kwargs)
if not isinstance(content, bytes):
content = content.encode(self._encoding)
return content
def close(self):
self.file.close()
def readable(self):
return True
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